Centerboard



F. A. GRAHAM. CENTERBOARDJ APPLICATION FILED AUG-13,1920! Patented Apr. 5

l/V l/E N TOR 4 Grain? UNITED STATES PATENT OFFICE.

CENTERBOARD'.

Specification of Letters Patent.

Patented Apr. 5, 1921.

Application filed August 13, 1920. Serial No. 403,374.

To all whom it may concern:

Be it known that I, FRANK ARoHIn GRAHAM, a citizen of the United States, and a resident of Harbor Springs, county of Emmet, and State of lVIichigan, have invented a new and Improved centerboard, of which the following is a full, clear, and exact description.

This invention relates to centerboards for use in sailing vessels, and has for an object the provision of a centerboard which is made of fabric which can be folded to 00- cupy a minimum space in the boat.

Another object of this invention is to provide a center board which may be easily and cheaply constructed.

A further object of this invention is to provide a center board which will not be injured if raised by striking an obstacle.

A still further object of this invention is to provide a center board which may be operated from the stern of the vessel without leaving the rudder.

Reference is to be had to the accompanying drawing forming a part of this specification, in which it is understood that the drawing illustrates only one form of the invention, and in which Figure 1 is a side elevation of a vessel with parts broken away to disclose the con struction.

Fig. 2 is a plan view of the vessel.

Fig. 3 is a sectional view through the vessel on the line 3-3 of Fig. 1.

Referring to the accompanying drawing by numerals, 10 indicates a sailing vessel or other boat which is provided with a mast 11 carrying a sail not shown. As commonly practised, a center board is usually pro vided for sailing vessels of small size to increase their lateral resistance in the water and thus provide better sailing qualities. My invention consists essentially in an improved construction of center board together with the mechanism for manipulating same. My improved center board consists in two heavy strips of material 12 which may be of woodor metal, and which are secured together by bolts 13. One end of the strips 12 is pivotally mounted in a housing 14 by means of a spindle 15 extending through water-tight stuifing boxes 16. The housing 14 is usually positioned above the keel of the boat and somewhat back of the mast 11. A strip of fabric 17 such as a piece of canvas is secured between the strips 12 at itslower end, and is secured atits upper end to a flat spring 18 fixed to the top of the housing 14 by a bolt 19. Instead of the fiat spring 18, coil spring may be provided so as to keep the fabric 17 taut when the strips 12 are in their lowermost position.

In order to raise and lower the strips 12 when desired from the stern of the boat without leaving the rudder 20, I provide a pulley 21 on the end of the spindle 15 inside the boat, and the ends of a pair of cables 22 are secured to opposite sides of said pulley 21. A coil spring 23 serves to connect the free end of each cable 22 to one end of a chain 24, said chain passing around and meshing with a sprocket wheel 25. The sprocket wheel25 is secured to a shaft 26, to one end of which is also secured a crank 27. The shaft 26 is rotatably mounted in suitable bearings 28, and a ratchet 29 is secured preferably to its lower end and is enga ed by a pivotally secured pawl 30.

n operation the strips 12 normally hang in their lowermost position as shown in Figs. 1 and 3, and the fabric 17 is held taut by the flat spring 18. When it is desired to raise the center board to pass an obstruction 'or for other reasons, the crank 27 is rotated which causes one of the springs 23 to become loose and the other one to become taut so that the pulley 21 and the spindle 15 is rotated-in the desired direction, thus raising the center board. The pawl 30 serves to engage the ratchet 29 and hold the center board in its uppermost osition.

I would state in conclusion t at while the illustrated example constitutes a practical embodiment of my invention, I do not limit myself strictly to the mechanical details herein illustrated, since manifestly the same can be considerably varied without departure from the spirit of the invention as defined in the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a centerboard, the combination with the centerboard housing of a boat, of a rigid element pivotally mounted in said housing adapted to extend below the keel of a vessel, and a flexible element extending between said vessel and said rigid element adapted to increase the lateral resistance of said boat when sailing.

2. In a centerboard, the combination with the centerboard housing of a boat, of a rigid element pivotally mounted in said housing adapted to extend below the keel of a vessel, a flexible element extending between said vessel and said rigid element adapted to increase the lateral resistance of said boat when sailing, and resilient means adapted to maintain said flexible, element taut when said rigid element is in its lowermost position.

3. A device as described in claim .1 characterized by means positioned in said boat for raising said centerboard about its pivot to its uppermost position.

4. In a device of the class described, the combination with a sailing vessel having a centerboard housing and a rudder, of a spindle passing through said housing, a rigid element pivotally supported by said spindle in said housing, a flexible element secured between said housing and said rigid element, a pulley secured to said spindle inside said boat, and means positioned adjacent the rudder of said boatadapted to cause the rotation of said pulley so as to raise said rigid element to its uppermost position.

5. A device as ClQSOIlbBCl lIl claim 4 characterized by a pair of cables having one end secured to opposite sides of said pulley, a shaft rotatably positioned adjacent the rudder of said boat, a sprocket wheel secured to said shaft, achain adapted to engage said sprocket wheel and having eachof its ends secured to one of said cables, and a,

most position.

7. In a device of the class described, the

combination with a sailing vessel, of a pivotally mounted centei'board associated with said vessel, means for moving said center board about its pivot, and a resilient element associated with said means adapted to permit the upward movement of said centerboard about its pivot when said centeriboard comes into contact with an obstacle,

FRANK ARCHIE GRAHAM. 

